1. Field of the Invention
The present invention pertains to aerosol containers and more particularly, to aerosol container valve cups configured with sidewalls terminating in a radially, outwardly extending flange adapted to seat on a circular shaped ring outlining a filling hole at one end of the container.
2. Description of the Prior Art
Aerosol containers, their dispensing mechanisms and methods of filling are well known in the art. Examples of various types of aerosol containers are found in U.S. Pat. Nos. 2,961,131 (Bradbury), 2,963,834 (Stanley, et al.), 3,477,195 (Chambers), 3,512,685 (Ewald), 3,995,666 (Michaels), 4,346,743 (Miller), and 4,441,634 (Meshberg).
Bradbury illustrates an aerosol bomb device having a cover which has its outer periphery formed as an annular flange 5 rolled over the edge 3 of the can (see FIGS. 2 and 4 of that patent). The base 7 of the cover has apertures 17. An apron 16 of flexible material such as nylon is placed below apertures 17 and is normally sealed shut against the apertures by the pressure of the contents. For injection of the pressure medium, the medium is supplied to orifices 17 under pressure and presses apron 16 away from the apertures (FIG. 4). If excessive pressure develops in the can during storage or use, the apron 16 bulges against projections 18 formed in the aperture 17. The projections 18 form small, temporary vent holes in the apron, permitting the escape of excess gas. After the venting is complete, the apron 16 resumes its ordinary shape, and the vent holes close up.
Stanley, et al., is directed to a system for filling and sealing receptacles, and shows the filling of a can 10 by first introducing the product into the can, placing the cup 15 thereon loosely, lifting the cup 15 off the can by means of vacuum suction (FIGS. 3 and 4 of that patent), introducing propellant in the liquid phase, and then replacing the cup 15 and crimping it in place on the can (FIG. 5).
Chambers illustrates a can containing a vertically collapsible, bellows-like accordion-pleated sack 40 which contains the product and separates it from a propellant. To charge the can with propellant without the need for providing a hole in the bottom of the can, the neck portion of the product sack is supported above the neck of the can and the propellant liquid is brought into the can through the space resulting between the can neck and the sack neck. In addition, grooves 52 are provided in an upper shoulder portion of the sack, which grooves serve as passages for the propellant liquid. A combined filling and crimping head supports the sack neck by means of a bracket 70 (see FIG. 4) and fills the can with a propellant, after which it forces the sack neck down into a close fit with the curled opening at the top of the can and crimps the down-turned peripheral flange 22 of the latter over the annular bead 23 provided at the periphery of the top opening of the can.
Ewald shows an aerosol container with an inner auxiliary plastic container 12. The open center tops of both the can 10 and the container 12 are closed by crimping a plastic-lined mounting cup 16 into the opening. A plastic disk 18 lines the inside of the cup and the space between the cup 16 and the plastic container 12, to provide a plastic-to-plastic seal, and to provide a closed, all-plastic container for the product and propellant with no exposure to the metal surface of the can 10 or mounting cup 16. This patent states that the can may be filled with product before the disk 18 and cup 16 are crimped into the can 10, or by pressure filling through the valve "in accord with customary practice." The plastic disk 18 (see FIGS. 2 and 3) may be extra thick at 30 to avoid the need for gasket material in that area.
Michaels pertains to a method for filling an aerosol spray dispenser containing liquid with a soluble gas propellant. According to the method to which this patent pertains, a mounting cup 12 is loosely placed on the top of can 10 containing a liquid 15. As shown in FIG. 2, a filling apparatus 16 is used to lift the cup 12 off the top of the can for filling. A vacuum is applied to cause air to flow from space 24 in the can upward around the bottom of mounting cup 12 to lift the cup into its raised or lifted position. Cup 12 is held against wall 22a, which prevents the cup from making the seal with a higher resilient member 23. Member 23 is then forced against the top of cup 12 to form a seal therewith, after which the cup 12 is again lifted off the top of the can 10 to permit injection of carbon dioxide or other suitable propellant (FIG. 4). After the propellant has saturated the liquid 15, the pressure drops and cup 12 is lowered onto the top of the can for crimping.
Miller relates to an aerosol container having an internal bag 28 to separate the product from the propellant. To provide the space between the neck of the product bag 28 and the can 18 to permit charging of the propellant into the space between the bag and the can, its neck extends above and through the top opening of the can to provide a space between them for propellant flow. The valve cup is placed on the top of the bag, and the two are shaped in such a way that a sealing flange of the valve cup engages an annular flange at the opening of the product bag, automatically clamping the two in sealing relation to each other. The product bag is made resilient so that upon initial application of the cup, the bag collapses vertically, forming a seal between the two elements. When the valve cup is released, the bag resiliently rises again to lift the valve cup and restore a clearance between the flange of the product bag and the flange of the can to permit propellant filling. After propellant filling, the valve cup is again depressed to clamp the container flange and the flange of the product bag together to seal against propellant escape.
Meshberg relates to filling a pressurized container comprising a mounting cup and a can containing both product and a pressurizing fluid, and shows a dispenser having a valve said to be adapted for fast pressure filling.
Aerosol containers and their associated valve cups are well known in the art, however, there is one recent problem associated with filling containers in a piston type dispenser.
This type of aerosol container normally has the usual one inch opening at the top which is adapted to receive a valve cup. The opening in the container has provisions for receiving the valve cup and ultimately, making a pressure type seal to insure against leakage of its contents, which is under pressure. A circular ring, or curl, surrounds the opening at the top of the container. The valve cup has sidewalls which fit into the opening at the top of the container. These sidewalls end in a radially, outward extending flange, which is shaped to seat on the curl encircling the opening of the container. The valve cup has a push type activated valve mounted at its center for dispensing the product within the aerosol container.
In a piston type aerosol dispenser, a beveled piston is placed at the bottom of the container and product is placed on top of the piston. The walls of the container act as a cylinder, against which the circumference of the piston fits. In filling the container, the valve cup is placed loosely in the hole at the top of the container. The flange on the valve cup rests on the curl or circular ring of the container top. Air is used to lift the valve cup and push product down around the piston to provide a product seal between the piston and the can walls. Under normal circumstances, valve cup lift is not obtained one hundred (100%) percent of the time. When valve cup lift is not obtained, the valve cup seats on the container curl, forming a seal which prevents proper operation of the filling apparatus. This results in non-functional units.
The problem of the valve cup flange prematurely seating on the container curl may occur in other aerosol filling processes when propellant is added. However, this problem does not create non-functional units to the extent that it does in piston type dispenser filling processes.